In the field of soft-actuators and soft-robotic applications, it is known to use fluidic networks embedded within soft structures whose deformation it is desired to control, by means of the pressure applied to the fluid embedded in the structure. The fluid applies pressure on the fluid-solid interface, and the solid is thus deformed. Some examples of such applications can be found in U.S. Pat. No. 6,772,673 to T. Seto et al, for “Flexible Actuator”, in WO2012/148472 by President and Fellows of Harvard College, for “Soft Robotic Actuators”, in WO2013/148340 by President and Fellows of Harvard College, for “Systems and Methods for providing Flexible Robotic Actuators”, and in WO1998/049976 by S. Huang, for “An Artificial Tubular Muscle and Application thereof”. These prior art documents describe the use of pressurized channels or networks of channels for generating motion, and especially bending motion in the flexible element in which the channels are incorporated. The main emphasis of all of these references is qualitative, in describing various embodiments by which controlled bending motion can be generated in the elements, either for use as soft robotic actuating elements, or, in the case of WO1998/049976, as an artificial muscle. The elements are generally designed by means of trial and error methods. In FR 2 907 421 to Airbus France SAS, for “Element de Panneau Deformable et Panneau le Comprenant”, there is described a deformable panel element, made of an elastomer body fortified with a frame of extendible members to limit its deformation, and incorporating an internal inflatable sealed chamber which can be filled with fluid. When the fluid is pressurized, the panel adopts a deformed configuration shape, which returns to its equilibrium shape when the pressure is released. In another implementation shown, two such panel elements are bonded together, so that the shape of the composite panel element is determined by the pressure of the fluid in both of the chambers.
However, in the above referenced prior art, the effects of the internally generated forces resulting from the pressurized channels or chambers, on the elastic and mechanical properties of the element in which they are embedded, have not been quantitatively investigated, and any novel material properties resulting therefrom and the practical application thereof are so far essentially uncharted.
Furthermore, the prior art has not considered the effect of the viscosity of the fluid used to pressurize the chambers, and the effects of the use of a highly viscous fluid are hitherto unknown
The disclosures of each of the publications mentioned in this section and in other sections of the specification, are hereby incorporated by reference, each in its entirety.